Audio Problems

The following information appeared in a news posting from Bryan Chee fomerly of Microsoft's NetMeeting team. It is one of the most lucid explanations of NetMeeting audio problems and the cures that I had seen. I have reproduced the post here verbatim for those that are interested. I have also included a newsgroup posting from Randy Smothers about AWE64 experiences that is probably useful no matter what sound card you are using.

Echo - Headsets and Mixers at the other end.

Echo you hear is almost always a configuration or setup program at the other end.

The most useful thing you can do to improve audio is to get a headset with integrated boom microphone, handset or super directional microphone and make sure your partners do the same - nothing fancy required just simple, cheap works well. This eliminates many of the "echo" problems, eliminates many of the problems of "constantly open microphone" that Bryan mentions with half duplex set-ups. I have a review of some devices that should help on my hardware page.

Another configuration problem causing echo can be that the audio mixer at the other end has included wave output in the recording mix ( whether this is possible or not is sound card dependent). See the section below on audio mixer configuration for NetMeeting.

You can find a selection of headsets available for purchase in the NetMeeting store.

What headset should I get?

Randy Smothers send this explanation of headset incompatibilities with sound cards to the discussion list:

"Many sound card makers (and motherboard makers where the sound chip is included in the motherboard) have reduced the voltage available on the microphone jack - possibly as a way to reduce hum and interference and probably as a way to cut costs. In either case, the result is the same, voltages below the 2.5 volts (+/- .25 volts) required by some microphone and/or headset makers.

The Andrea headsets/mikes come in two varieties - model numbers that start with either "ANC" or "NC." The "ANC" units use "Active Noise Canceling" circuitry to improve mike output quality and to reduce background noise. This "ANC" circuitry requires a higher voltage to operate than some sound cards, computers or laptops provide. Specifically, to quote directly from the documentation found in the ANC-550 package: "Some computers and laptops without sufficient power (2.25 volts) in the microphone port will require a three-volt auxiliary power supply (APS-100) ..."

The Andrea "NC" units use "Noise Canceling" features to reduce the background noise. These units require less voltage than the "ANC" units and will will work with as little as 1.25 volts.

A number of other headset/microphone makers also put out two different versions of their equipment, one requiring less voltage (but at the cost of being less capable) than the other. "

The moral of the story -- you may have to be careful when you buy a headset to ensure compatibility with your sound card.

"I can't be heard/ I can hear myself in my speakers - mixer setting problem ?"

Make sure that your microphone is setup in the mixer to not play back locally and to be the only device being recorded ( i.e. sent to the other end)-- you shouldn't hear yourself speak through your speakers (unless you have one of the "echo" problems mentioned before).

Make sure to set the mixer so that the microphone  is "muted" on playback and "selected" on record. For good measure it might be sensible to use only the "Wave" device on playback and only the "Microphone" on record. Others can be added back as you need them and determine that they don't cause problems in the mix.

This is what I see in my playback mixer which comes up by default when the speaker icon in the system tray is double clicked (every card is slightly different but you should see something similar):

The options menu, properties item brings up:

Make sure all the items in "Show the following..." are checked so that you can see everything that could be in the mix.

Selecting "Recording" brings up the record mixer:

Again make sure all items are selected in the "Show the following.." selection for the record mixer. If you like you can both the Playback and Record mixers up at the same ( start two from the speaker icon) -- and start NetMeeting to see the effect ( you can start up other devices ( midi, CD audio) and play with the mixer to see the effect if you are adventuresome).

Direct Sound

Also try to have a widely used sound card so that full duplex drivers exist and work and so that DirectX drivers exist and work. If you are having problems with all partners - turn off DirectSound and full duplex, especially if you have an old or non-standard sound card (there is a neat utility to turn off DirectSound at The NetMeeting Place). Microsoft has registry hacks to do it as well. Another recent suggestion was to turn off "Hardware acceleration" on playback, recording or both in the Sound tab (advanced properties) of the Multimedia item in the Control Panel.

This problem seems to have become worse with Win98 -- perhaps because DirectX is standard part of release.

In version 3.x this problem is very much lessened - the default for this option is off and the option to turn it on is available on the audio options tab.

"I can hear but can't be heard - a SLIRP problem?"

Becoming much less common but one of the causes of the "I can hear but can't be heard" that Bryan didn't mention in his post (but are probably discussed somewhere on Microsoft's site) is that you or your partner are on SLIRP access line (evidence of this is if you or your partner see two of the other person in the Current Call window)

To solve this you or your partner or both need a new ISP that supports PPP.

"I can hear but can't be heard or seen - a router, proxy or firewall problem?"

Another cause of this problem is that you or your partner are behind a router or firewall that does NAT (most firewalls are of this type as are IP Masquerade tools (LINUX) or one of  NAT32, NAT1000, Sygate or like products) or incorrectly configured proxy.

A way to determine if this is a likely problem is to find out if your IP address is from the "private" set  ( 10.x.x.x, 172.16.x..x to 172.31.x.x and 192.168.x.x are the numbers allocated for that use). In V 3 the about box lists your current IP address - in V 2 using "winipcfg" will display the current IP address

Bandwidth and audio (or video breakup) break up

Another topic Bryan mentions is that your bandwidth settings may be set "too high" -- a thing to remember is that "too high" may mean "too high" for the current network traffic -- these bandwidth settings are intended as a basis for negotiation between you and your partner to determine audio codec usage. Using a codec that compresses more may produce lower quality audio but with less "choppiness" (probably desirable). Another thing to remember is that your settings may be correct but your partner's may be "too high". If you find that "choppiness" is unbearable - shut down, change your bandwidth setting to the lowest value you can, re-establish the call. Unfortunately you cannot change mid call.

NetMeeting has a slightly lower bandwidth codec that can be used -- before the call, using the "Advanced" button in the audio options tab, click "Manually configure compression settings" and select the displayed codec  The bandwidth requirements are not that much less than normally used codecs but may be enough different to reduce break up in some cases.

Detecting routers causing audio/video breakup

Most often this symptom is caused by router on the route between the parties dropping packets ( this is what they do when they are busy). TCP protocols ( like those used for web, mail and news access) recover from lost packets with the only symptom being slower access. UDP protocols ( like those used for streaming audio/video and NetMeeting audio) do not recover by design and this results in audio/video dropouts ( some of which can be partially compensated for).

I use a tool called Ping Plotter available from Nessoft ( I have it running minimized in my system tray all the time) that is a graphical trace route tool to spot router problems:

I use a small batch file -- I call mine findip.bat (made runnable from the desktop - based on a suggestion from Tim Andrews) that will determine the IP address of the other party (it runs netstat, and extracts the line with 1720 -- a critical H.323 port number -- the IP address of the other party is in the line as well)

Knowing it now there is not much you can do -- except complain to the appropriate ISP but at least it gives you a hint when your ISP sucks.

Periodic Slowdowns or Audio/Video Stopping or Freezing

Many people seem to be experiencing periodic glitches (like every 15 minutes) where audio gets choppy or garbled. This is usually caused by something on your system or your partner's that runs periodically -- possible culprits:

Been seeing some issues come up about audio quality and audio problems. Hopefully these tips will help some of you with these issues.

Audio quality
=========
Echo
-----------

Whenever you speak you'll hear yourself delayed about a second or two later. This is usually caused when the person you are talking to is feeding your audio back to you from their speakers to their microphone so you hear the audio again on your side. The other person will need to adjust their microphone sensitivity, move the mic away from the speakers, run the audio tuning wizard, or just get headsets.

http://support.microsoft.com/support/kb/articles/Q166/0/38.asp

Choppy audio
-------------------

There's a lot of things that can cause choppy audio. Usually it turns out to be a combination of either bandwidth or processor. Try toggling between the codecs and manually set the audio codec to a less intensive codec such as L&H16 (goto TOOLS-OPTIONS-AUDIO-ADVANCED... then manually set the codec by checking the box and moving the codec to the top of the list). Turn off and disable any other non-critical apps running on your machine. Also check your bandwith settings... it may be set too high. (TOOLS-OPTIONS-GENERAL). See the following KB as well.

http://support.microsoft.com/support/kb/articles/Q165/6/22.asp

Distortion and muffled sound
--------------------------------------------
This can and usually is caused with the user being too close to their microphone. Have the user back away from their mic until it clears up. Other times it can be caused from "puffs of air" or "spitting" into the microphone. Cover or shield the microphone with some spongy foam, tissue, or a fuzzy "hamster" gizmo like the media uses on their boom mics to absorb the excess air / spit. (yes not graceful but a tip none the less. some people swear by it.) This problem can be cleared up by moving the mic away as well.

Audio Problems
===============

Can Hear or can't be heard... vice versa
----------------------------------------------------
This is usually due to a sensitive microphone and half duplex. If the microphone is too sensitive, then it may "lock" the audio into sending all the time and will lock the one audio channel (half duplex). Get full duplex drivers or use / mute audio like a CB when done speaking. See the following KB for more info.

http://support.microsoft.com/support/kb/articles/q174/6/11.asp

Can Hear or can't be heard... part 2
------------------------------------------------
A subset of this same problem could be with DirectSound. Some cards dont support full duplex with directsound and thus the behavior above. Disable directsound in NetMeeting. Disabling directsound in NetMeeting will not disable directsound on your system. See the following KB.

http://support.microsoft.com/support/kb/articles/q179/6/46.asp

Audio skips like a record
-------------------------------
On older versions of NetMeeting 2.1, you may hear a line repeated over and over again... example. "Jack and Jill went up the hill.... up the hill... up the hill... up the hill..." If this is a problem, upgrade your sound drivers and to the latest version of NetMeeting.

http://support.microsoft.com/support/kb/articles/q183/1/26.asp

For other issues with NetMeeting see the NetMeeting support faq.

http://support.microsoft.com/support/netmeeting/faq/

as well as the NetMeeting readme

http://support.microsoft.com/support/netmeeting/readme/

for a non-microsoft sponsored site with a plethora of information see

http://www.netmeet.net/

--
Bryan Chee
NetMeeting Team
msnetmtg@microsoft.com

From: "Randy Smothers"
Subject: AWE 64 woes.
Date: Tue, 14 Jul 1998 09:40:53

I have several users who also use the AWE 64 and my experience has been that the AWE64 is prone to "overdriving" the input side of NetMeeting, causing broken/choppy audio at the recipient's end. Such "overdriving" is often the result of too much input volume at the microphone. We've also found that if we are using better quality (more sensitive) microphones, background noises are often being picked up by the mic and sent over NetMeeting even when the user is not talking. Then, when the user does talk, the combination of background noise and the user's voice ends up overwhelming either the sound card or NetMeeting or both.

We've generally solved the problem by either:

1. Setting the mic input somewhat lower than the audio tuner sets it
2. Having the user speak softer or sit further from the microphone
3. Using a (somewhat) directional, sound attenuating microphone
4. Using a headset with a sound attenuating boom microphone

Randy Smothers